ChemTech

  UNIT 3 Liquid – Liquid EXTRACTION Explanation of Concept Extraction is a unit operation which separate a desired substance when it is mixed with others.The mixture is brought into intimate contact with a solvent in which the substance of interest is soluble,but the other substances present are insoluble Extractions use two immiscible phases (these are phases that do not mix, like oil and water) to separate the substance from one phase into the other. The phases are extract phase and raffinate phase. The residual solution from which solute is removed is called raffinate and the solvent rich product of   operation is called extract. The extract phase contains desired product in large proportion. Difference between extraction and distillation. Distillation Extraction 1)Distillation or fractionation is an operation in which the constituents of a liquid mixture are separated by using thermal energy 1)Extr...

 GAS ABSORPTION Gas Absorption -Gas absorption is a unit operation in which gas mixture is contacted with liquid for preferentially dissolving one or more constituents of gas providing a solution of them in liquid. Example Gas from by product coke ovens is washed with H2O to remove NH3 and again with an oil to remove benzene and toluene vapours.   Comparison of absorption with distillation Absorption                                            Distillation 1 Gas absorption is separation of constituents of gas mixture It is related with separation of constituents of liquid mixture. 2 The constituents of gas mixture are separated by using liquid solvent The constituents of liqu...